Photoelectric device for automatically correcting the carbons of projectors

ABSTRACT

Photoelectric device for the automatic correction of the lamp carbons of projectors. A lamp has two photoelectric cells and an appropriately diaphragmed lens located laterally of the lamp in front of the arc of light and spaced so as not to be damaged by the heat. The amplified image from the carbons is projected onto the two photoelectric cells which are sensitive to the light of the arc. Two photoelectric relays are provided acting independently, one for the positive carbon and one for the negative carbon, so that they send the respective effects of their sensitivity to each one of the two photoelectric cells. An electromagnet having a solenoid is activated by the relays located in the advancing speed variator of the carbons, comprising means for correcting the malformed crater caused by combustion in the positive carbon and the negative carbon. A guiding support for the negative carbon maintains such carbon in an exact position in relation to the positive carbon. The negative carbon carrier is slightly movable in its vertical position as well as in its horizontal position, so that the advancing of the negative carbon may be done without difficulty.

United States Patent [72 1 Inventor Jose Tomas Barrientos Luque SanMarcos, No.23. Priego De Cordoba,

Spain 1211 Appl No 806,241 [22] Filed Mar. 11, 1969 [45 Patented July27, 1971 [32] Priority Mar. 12, 1968 331 Spain [311 136,950

[54] PHOTOELECTRIC DEVICE FOR AUTOMATICALLY CORRECTING THE CARBONS2,151,194 3/1939 Desormeaux 314/134 X 2,469,664 5/1949 Murch 314/63 X2.487.024 11/1949 Mathison.... 314/63 X Primary Examiner Roy LakeAssistant Examiner-E. R. La Roche Attorney-Wenderoth, Lind & PonackABSTRACT: Photoelectric device for the automatic correction of the lampcarbons of projectors. A lamp has two photoelectric cells and anappropriately diaphragmed lens located laterally of the lamp in front ofthe arc of light and spaced so as not to be damaged by the heat. Theamplified image from the carbons is projected onto the two photoelectriccells which are sensitive to the light of the arc. Two photoelectricrelays are provided acting independently, one for the positive carbonand one for the negative carbon, so that they send the respectiveeffects of their sensitivity to each one of the two photoelectric cells.An electromagnet having a solenoid is activated by the relays located inthe advancing speed variator of the carbons, comprising means forcorrecting the malformed crater caused by combustion in the positivecarbon and the negative carbon. A guiding support for the negativecarbon maintains such carbon in an exact position in relation to thepositive carbon. The negative carbon carrier is slightly movable in itsvertical position as well as in its horizontal position, so that theadvancing of the negative carbon may be done without difficulty.

PHOTOELECTRIC DEVICE FOR AUTOMATICALLY CORRECTING TI-IE CARBONS OFPROJECTORS This invention furnishes the means for achieving automatic 1stabilization and uniformity in the arc lamp consumption of the positivecarbon, and to prevent the malformed crater which invariably appears onthe electrode itself.

There are units which automatically regulate the optimum distancebetween the electrodes in such a way that they advance as naturalconsumption occurs. Thus, they maintain the proper distance and also thefocal point of the lamp since the positive and negative carbons havetheir own independent means of propulsion. These are generally automatedby utilizing photoelectric cells or any other type of device sensitiveto light from the arc lamp. Thus, for example, varying resistance when aphotoelectric cell receives light transmits its effect to appropriatelylocated relays which act on the carbons being consumed. However, inpractice it has been proven that employment of such regulating devicesdoes not prevent the serious drawback resulting from the malformation orcrater which originates on the negative carbon as it is consumed. Thisis detrimental to the function of the luminous projector since it ishighly advisable that consumption of the positive carbon be 7 as regularas possible. Consumption should be maintained on a plane perpendicularto the longitudinal axis of the carbon. An object of the invention is toremove the above disadvantages.

Insofar as to closeness of the carbons, the device may be any one of theknown types. For example, those constituted on the basis of a lenslocated on the side of the lamp which receives the image from thecarbons and, adequately enlarged, projects it on two photoelectric cellswhich upon being illuminated act upon relays or speed changers whichadvance the electrodes and thus maintain the focal point and regulationof the arc.

The correcting device to which this invention relates is particularlydesigned to act in collaboration with the aforementioned system forbringing the electrodes together. Basically, it consists of severalphotoelectric cells which function to change the position of the carbonsfacing each other in the horizontal and vertical. In this manner apossible deformation of the positive carbon crater is corrected.

With the above and other objects in view which will become apparent fromthe detailed description below, some preferred embodiments of theinvention are shown in the drawings, in

which:

FIG. 1 is a schematic view showing the positive and negative carbonsresting on their corresponding bases.

FIG. 2 is a similar view showing the location or status of thecorrecting elements when the consumption of the positive electrodeoccurs without deformation.

FIG. 3 is a schematic view showing the formation of a vertical crater onthe positive electrode, with greater consumption in the higher area ofthe carbon. I

FIG. 4 is a similar view also showing a malformation of the positivecarbon which is vertical. In this case there is a higher degree ofconsumption in the lower area of the carbon.

FIG. 5 is a schematic view of a modification in the correcting devicesshown in the foregoing figures.

In FIG. I a base 8 supports the negative carbon and is similar to thebase 9 for the positive carbon. This base-guide 8 maintains the properposition of its carbon with relation to the positive and independentnegative carbon, whether in a straight line or not.

The negative carbon holder will be mechanized to its base in such a waythat it can pivot slightly either horizontally or vertically in orderthat the negative carbon, supported on its guide, may effortlesslyadvance. I

Automatic correction of the crater will be effected in two positions:vertical and horizontal. For the first position-FIG. Z-the carbon imageis taken from the L lens horizontally, cooperating with the two cells 10and 11. These cells independently transmit their effects to relays 10'and II. The relays in turn transmit continuous current to a double coil12 horizontally located in front of the luminous arc 5 in such a waythat the magnetic effect of its iron nucleus 13 reaches the are 5. Itfunctions as follows:

As shown in FIG. 2 no cell is active since the carbons are in properposition. Consequently relays 10' and 11' are open and no current passesto the coil 12. Supposing that nothing carbon is consumed in a regularfashion, all the cells 10 and 11 go into action. They activate theirrespective relays l0 and 11 which circulate a continuous current throughthe double coil 12 in the direction indicated by arrows. As will benoted these are the same but go in different direction s, their magneticeffects are cancelled and nothing happens.

7 shown by the arrow. It magnetizes the iron nucleus which influencesits action on the electric current originating the arc according toelectrodynamic laws and perpendicularly shifts the magnetic flow in onedirection or another, depending upon magnetic polarity (in this casedownward). It more intensely attacks part a of the carbon to a pointwhere it is consumed and the crater corrected, thus letting light intothe cell 11. This activates the relay 11' from which current passes tothe other coil which, as has been stated, is in an opposite direction,and its effects compensated. Thereby magnetism in the nucleus iscancelled. Also, as the cell 10 is darkened, it disconnects the relayl0. and is left without current.

Let us again suppose that the crater is formed vertically but in anopposite direction as shown in FIG. 4. The cell 11 activates the relay11, while relay 10 is open because its cell 10 is in darkness, currentcirculating through half of coil 12 as indicated by the arrow, howeverin a direction opposite to that shown in FIG. 3. The nucleus thereforemagnetizes but its polarity is contrary to the above case and the effecton the current of the arc is also in reverse of the above. It is shiftedupward and consequently will more intensely attack part b of thepositive carbon until consumption is equaled as in the foregoing case.This device permits correction of the crater in both vertical directionsof the carbon at top and bottom.

Everything is the same as in the preceding case when correcting the twohorizontal directions, right and left, of the crater. With a similardevice not shown we take the image from the carbons vertically from thetop. The coil is placed vertically also, under the are as indicated inFIG. 1, to the side of the base of the positive carbon guide.

It may be that the deformed crater .surface be inclined; that is to say,it is neither vertical nor horizontal. Then both activating devicesoperate simultaneously on the point where correction is necessary.

The crater may also be corrected as shown in FIG. 5. An electricallyinsulated crank 15 is placed on an axle l4 behind reflecting mirror 2 ofthe lamp. Part 15 passes by mirror 2 and approaches the negative carbonextreme end and serves as a guide-base therefor. Part 16 of the iron,goes through the interior of a coil 17 until it faces the north andsouth poles of another coil 18 with double coil. A spring 19 keeps thecrank l516 steady and centered between poles north and south.

Operation is as follows: As previously explained, when the crater of thepositive electrode activates the cells which have been placed over itsimage for correction and the respective relays are activated, thesetransmit the current to the coil 18 and to the double coil relay 20.Both double coils are connected on a parallel and operatesimultaneously.

When the crater is correct the respective cells activate their relays atthe same time and there is no effect on the coil 18 nor on the relay 20,because the current in the two coils are equal and opposite. If thecrater tends to deform, one of the cells will be in the light and theother in darkness. In this case there will be current in one branch onlyand consequently in half of the relay coil 20 which is then activated,shutting off the contacts 21. Likewise there will be current in one coilonly 18 magnetizing its poles to the arm 16 with the indicated polarity.According to the laws of magnetism, poles of the same sign repel eachother, while opposites attract. Therefore, the stick leaves its positionand pushes the negative carbon upward until it corrects the crater,equalizing the light over both cells. The effect is deactivated both inthe coil 18 and the relay 20. The latter stops passage of current to-thecoil 17 causing the magnetic force of the arm 16 to cease and it returnsto its original position.

If we consider that the crater occurs in reverse to the foregoing,everything functions similarly. The relay 20 is activated and transmitscurrent to the coil 17 andsimultaneously to coil 18, therefore there iscurrent in the coil. Since polarity is contrary to the above, the stickl6 shifts to the opposite, the negative carbon decreases and incorrecting the crater of the positive carbon, everything returns to itsoriginal state.

The generic term cells has been employed throughout the description. Itshould be clarified that this refers to phototubes, photodiodes,phototransistors, etc., as well as to any other elements, which throughincidence of infrared, red, blue, violet, ultraviolet, etc. radiationsgenerate or modify electric, electromagnetic or electronic currents forcorrections for which this invention is designed.

I claim:

1. Device for correcting a crater formed on the carbon electrode of anelectric arc lamp comprising spaced carbon electrodes of an arc lamp,photoelectric cells, means for projecting the image of the ends of saidelectrodes adjacent the arc towards said cells, a support guide, aholder for the negative electrode mounted on said support guide to pivotuniversally so that said negative electrode may advance even when thelinear facing position thereof changes with respect to the positivecarbon electrode and means actuated by said cells controlling thepivoting of said holder.

2. Device according to claim 1 wherein correction of a positive carboncrater is made by placing an axle and insulated stick behind thereflecting mirror of the lamp which is beyond the mirror and approachthe end of the negative carbon electrode to which it will serve as aguide-support, part of said stick faces the poles of a coil with doublesprings in which it is centered by means of a spring for that effect,said assembly is disposed so that when a crater appears on the positivecarbon electrode the cells'will activate since they are placed so thatsaid image activates the appropriate relay.

3. Device according to claim 1 wherein when the positive carbonconsumption proceeds properly said image simultaneously activatespredetermined cells, relays connected to said cells independentlyactivated, a double coil located in front of the arc of light connectedto said relays so that the magnetic effect of the nucleus of said coilreaches the arc whereby, as long as consumption of the positive carbonelectrode is regular, no correction will occur since all the'cells willbe active and consequently because of opposition, their effect on saidrelays and coil is cancelled.

4. Device according to claim 3 wherein upon appearance of a vertical orhorizontal crater on the positive carbon electrode its image istransmitted to a cell becoming active corresponding to the point wherethe crater has occurred, while the remaining cells remain in darkness,then only the relay functioning by said active cell will transmitcurrent in one direction alone to one coil of said double coil so thatits nucleus will be magnetized and its effect will influence the currentproducing the arc to flow perpendicularly to the correcting positionwhich will depend upon the acquired polarity signal and the positivecarbon will be more intensely attacked on the side opposite the craterand the deformation is automatically corrected.

5. Device according to claim 4 wherein once automatic correction of thecrater occurs, the cell which has been in darkness will be in the lightbecause there has been a proper consumption of the positive carbonelectrode, said last named cell activates the corresponding relay whichwill transmit current to the second coil so that the effect of thenucleus is cancelled and correction completed.

6. Device according to claim 5 wherein two groups of cells

1. Device for correcting a crater formed on the carbon electrode of anelectric arc lamp comprising spaced carbon electrodes of an arc lamp,photoelectric cells, means for projecting the image of the ends of saideleCtrodes adjacent the arc towards said cells, a support guide, aholder for the negative electrode mounted on said support guide to pivotuniversally so that said negative electrode may advance even when thelinear facing position thereof changes with respect to the positivecarbon electrode and means actuated by said cells controlling thepivoting of said holder.
 2. Device according to claim 1 whereincorrection of a positive carbon crater is made by placing an axle andinsulated stick behind the reflecting mirror of the lamp which is beyondthe mirror and approach the end of the negative carbon electrode towhich it will serve as a guide-support, part of said stick faces thepoles of a coil with double springs in which it is centered by means ofa spring for that effect, said assembly is disposed so that when acrater appears on the positive carbon electrode the cells will activatesince they are placed so that said image activates the appropriaterelay.
 3. Device according to claim 1 wherein when the positive carbonconsumption proceeds properly said image simultaneously activatespredetermined cells, relays connected to said cells independentlyactivated, a double coil located in front of the arc of light connectedto said relays so that the magnetic effect of the nucleus of said coilreaches the arc whereby, as long as consumption of the positive carbonelectrode is regular, no correction will occur since all the cells willbe active and consequently because of opposition, their effect on saidrelays and coil is cancelled.
 4. Device according to claim 3 whereinupon appearance of a vertical or horizontal crater on the positivecarbon electrode its image is transmitted to a cell becoming activecorresponding to the point where the crater has occurred, while theremaining cells remain in darkness, then only the relay functioning bysaid active cell will transmit current in one direction alone to onecoil of said double coil so that its nucleus will be magnetized and itseffect will influence the current producing the arc to flowperpendicularly to the correcting position which will depend upon theacquired polarity signal and the positive carbon will be more intenselyattacked on the side opposite the crater and the deformation isautomatically corrected.
 5. Device according to claim 4 wherein onceautomatic correction of the crater occurs, the cell which has been indarkness will be in the light because there has been a properconsumption of the positive carbon electrode, said last named cellactivates the corresponding relay which will transmit current to thesecond coil so that the effect of the nucleus is cancelled andcorrection completed.
 6. Device according to claim 5 wherein two groupsof cells are provided to act independently in the correction of cratersoccurring either vertically or horizontally and which act jointly whenthe crater or malformation in the positive carbon electrode occurs in amixed position when vertically inclined and to one side.